update-faxUpdate a fax record's read state and/or comment.
Side effects: modifies fax record metadata.
| Name | Required | Description | Default |
|---|---|---|---|
| fax_id | Yes | Fax ID to update. | |
| payload | Yes | Update payload with is_read and comment. | |
| user_id | No | Fax.Plus user ID. Default: self. |
| Name | Required | Description | Default |
|---|---|---|---|
| fax_id | Yes | ||
| updated | Yes | ||
| user_id | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and readOnlyHint=false. The description adds 'Side effects: modifies fax record metadata,' which is mildly useful but does not disclose permissions, auth needs, or scope. It does not contradict the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences, front-loaded with the core purpose and a clear side-effects note. No filler, though the wording could be tightened to avoid the 'and/or' ambiguity.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Despite complete schema coverage and an output schema, the description omits critical usage context: the payload fields are mandatory, and the tool should be distinguished from bulk-update-faxes and update-outbox-fax. An agent cannot reliably decide between siblings from this description alone.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, giving a baseline of 3, but the description's 'read state and/or comment' conflicts with the schema, which requires both comment and is_read in the payload. This actively misleads agents about the required payload shape.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Update a fax record's read state and/or comment') and identifies the fields being updated. It does not explicitly differentiate from update-outbox-fax or bulk-update-faxes, but the resource and scope are clear enough.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance on when to use this tool versus its siblings such as bulk-update-faxes or update-outbox-fax. The description implies single-fax updates but never states exclusions, alternatives, or prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.